<title>GCD</title><link href="http://hzoi.com/tomorrow.css" rel="stylesheet"><div class="ui existing segment"><pre><code><span class="pl-cp">#include</span><span class="pl-cpf">&lt;cstdio&gt;</span><span class="pl-cp"></span>
<span class="pl-cp">#include</span><span class="pl-cpf">&lt;cstdlib&gt;</span><span class="pl-cp"></span>
<span class="pl-cp">#include</span><span class="pl-cpf">&lt;cstring&gt;</span><span class="pl-cp"></span>
<span class="pl-cp">#include</span><span class="pl-cpf">&lt;algorithm&gt;</span><span class="pl-cp"></span>
<span class="pl-k">using</span> <span class="pl-k">namespace</span> <span class="pl-n">std</span><span class="pl-p">;</span>
<span class="pl-k">typedef</span> <span class="pl-kt">long</span> <span class="pl-kt">long</span> <span class="pl-n">ll</span><span class="pl-p">;</span>

<span class="pl-n">ll</span> <span class="pl-nf">euler</span><span class="pl-p">(</span><span class="pl-n">ll</span> <span class="pl-n">x</span><span class="pl-p">)</span>
<span class="pl-p">{</span>
    <span class="pl-n">ll</span> <span class="pl-n">res</span> <span class="pl-o">=</span> <span class="pl-n">x</span><span class="pl-p">;</span>
    <span class="pl-k">for</span><span class="pl-p">(</span><span class="pl-kt">int</span> <span class="pl-n">i</span><span class="pl-o">=</span><span class="pl-mi">2</span> <span class="pl-p">;</span><span class="pl-n">i</span><span class="pl-o">*</span><span class="pl-n">i</span><span class="pl-o">&lt;=</span><span class="pl-n">x</span> <span class="pl-p">;</span><span class="pl-n">i</span><span class="pl-o">++</span><span class="pl-p">)</span>
    <span class="pl-p">{</span>
        <span class="pl-k">if</span><span class="pl-p">(</span><span class="pl-n">x</span><span class="pl-o">%</span><span class="pl-n">i</span> <span class="pl-o">==</span> <span class="pl-mi">0</span><span class="pl-p">)</span>
        <span class="pl-p">{</span>
            <span class="pl-n">res</span> <span class="pl-o">=</span> <span class="pl-n">res</span><span class="pl-o">/</span><span class="pl-n">i</span><span class="pl-o">*</span><span class="pl-p">(</span><span class="pl-n">i</span><span class="pl-o">-</span><span class="pl-mi">1</span><span class="pl-p">);</span>
            <span class="pl-k">while</span><span class="pl-p">(</span><span class="pl-n">x</span><span class="pl-o">%</span><span class="pl-n">i</span><span class="pl-o">==</span><span class="pl-mi">0</span><span class="pl-p">)</span> 
              <span class="pl-n">x</span><span class="pl-o">/=</span><span class="pl-n">i</span><span class="pl-p">;</span>
        <span class="pl-p">}</span>
    <span class="pl-p">}</span>
    <span class="pl-k">if</span><span class="pl-p">(</span><span class="pl-n">x</span><span class="pl-o">&gt;</span><span class="pl-mi">1</span><span class="pl-p">)</span> 
      <span class="pl-n">res</span> <span class="pl-o">=</span> <span class="pl-n">res</span><span class="pl-o">/</span><span class="pl-n">x</span><span class="pl-o">*</span><span class="pl-p">(</span><span class="pl-n">x</span><span class="pl-o">-</span><span class="pl-mi">1</span><span class="pl-p">);</span>
    <span class="pl-k">return</span> <span class="pl-n">res</span><span class="pl-p">;</span>
<span class="pl-p">}</span>

<span class="pl-kt">int</span> <span class="pl-nf">main</span><span class="pl-p">(){</span>
    <span class="pl-kt">int</span> <span class="pl-n">T</span><span class="pl-p">;</span>
    <span class="pl-n">scanf</span><span class="pl-p">(</span><span class="pl-s">&quot;%d&quot;</span><span class="pl-p">,</span><span class="pl-o">&amp;</span><span class="pl-n">T</span><span class="pl-p">);</span>
    <span class="pl-k">while</span><span class="pl-p">(</span><span class="pl-n">T</span><span class="pl-o">--</span><span class="pl-p">)</span>
    <span class="pl-p">{</span>
        <span class="pl-n">ll</span> <span class="pl-n">n</span><span class="pl-p">,</span><span class="pl-n">m</span><span class="pl-p">;</span>
        <span class="pl-n">scanf</span><span class="pl-p">(</span><span class="pl-s">&quot;%I64d%I64d&quot;</span><span class="pl-p">,</span><span class="pl-o">&amp;</span><span class="pl-n">n</span><span class="pl-p">,</span><span class="pl-o">&amp;</span><span class="pl-n">m</span><span class="pl-p">);</span>
        <span class="pl-n">ll</span> <span class="pl-n">ans</span> <span class="pl-o">=</span> <span class="pl-mi">0</span><span class="pl-p">;</span>
        <span class="pl-k">for</span><span class="pl-p">(</span><span class="pl-n">ll</span> <span class="pl-n">i</span><span class="pl-o">=</span><span class="pl-mi">1</span> <span class="pl-p">;</span><span class="pl-n">i</span><span class="pl-o">*</span><span class="pl-n">i</span><span class="pl-o">&lt;=</span><span class="pl-n">n</span> <span class="pl-p">;</span><span class="pl-n">i</span><span class="pl-o">++</span><span class="pl-p">)</span>
        <span class="pl-p">{</span>
            <span class="pl-k">if</span><span class="pl-p">(</span><span class="pl-n">n</span><span class="pl-o">%</span><span class="pl-n">i</span> <span class="pl-o">==</span> <span class="pl-mi">0</span><span class="pl-p">)</span>
            <span class="pl-p">{</span>
                <span class="pl-k">if</span><span class="pl-p">(</span><span class="pl-n">i</span> <span class="pl-o">&gt;=</span> <span class="pl-n">m</span><span class="pl-p">)</span>
                <span class="pl-p">{</span>
                    <span class="pl-n">ans</span> <span class="pl-o">+=</span> <span class="pl-n">euler</span><span class="pl-p">(</span><span class="pl-n">n</span><span class="pl-o">/</span><span class="pl-n">i</span><span class="pl-p">);</span>
                <span class="pl-p">}</span>
                <span class="pl-k">if</span><span class="pl-p">((</span><span class="pl-n">n</span><span class="pl-o">/</span><span class="pl-n">i</span><span class="pl-p">)</span><span class="pl-o">&gt;=</span><span class="pl-n">m</span> <span class="pl-o">&amp;&amp;</span> <span class="pl-n">n</span><span class="pl-o">/</span><span class="pl-n">i</span> <span class="pl-o">!=</span> <span class="pl-n">i</span><span class="pl-p">)</span>
                <span class="pl-p">{</span>
                    <span class="pl-n">ans</span> <span class="pl-o">+=</span> <span class="pl-n">euler</span><span class="pl-p">(</span><span class="pl-n">i</span><span class="pl-p">);</span>
                <span class="pl-p">}</span>
            <span class="pl-p">}</span>
        <span class="pl-p">}</span>
        <span class="pl-n">printf</span><span class="pl-p">(</span><span class="pl-s">&quot;%I64d</span><span class="pl-se">\n</span><span class="pl-s">&quot;</span><span class="pl-p">,</span><span class="pl-n">ans</span><span class="pl-p">);</span>
    <span class="pl-p">}</span>
    <span class="pl-k">return</span> <span class="pl-mi">0</span><span class="pl-p">;</span>
<span class="pl-p">}</span>
</cpde></pre></div>